package org.example.template.utils;

import cn.hutool.core.date.DateTime;
import cn.hutool.core.date.DateUtil;
import org.apache.velocity.shaded.commons.io.FilenameUtils;
import org.example.template.common.Constants;
import org.example.template.common.CustomException;
import org.springframework.util.DigestUtils;
import org.springframework.web.multipart.MultipartFile;

import java.io.File;
import java.io.IOException;

/**
 * 文件上传工具类
 *
 * @author
 */
public class FileUploadUtils
{
    /**
     * 默认大小 50M
     */
    public static final long DEFAULT_MAX_SIZE = 50 * 1024 * 1024;

    /**
     * 默认的文件名最大长度 100
     */
    public static final int DEFAULT_FILE_NAME_LENGTH = 1000;

    public static final String[] DEFAULT_ALLOWED_EXTENSION = {
            // 图片
            "bmp", "gif", "jpg", "jpeg", "png","mp4",
            // word excel powerpoint
            "doc", "docx", "xls", "xlsx", "ppt", "pptx", "html", "htm", "txt",
            // 压缩文件
            "rar", "zip", "gz", "bz2",
            // pdf
            "pdf" };

    /**
     * 根据文件路径上传
     *
     * @param baseDir 相对应用的基目录
     * @param file 上传的文件
     * @return 文件名称
     * @throws IOException
     */
    public static final String upload(String baseDir, MultipartFile file) throws IOException
    {
        try
        {
            return upload(baseDir, file, DEFAULT_ALLOWED_EXTENSION);
        }
        catch (Exception e)
        {
            throw new IOException(e.getMessage(), e);
        }
    }

    /**
     * 文件上传
     *
     * @param baseDir 相对应用的基目录
     * @param file 上传的文件
     * @param allowedExtension 上传文件类型
     * @return 返回上传成功的文件名
     * @throws IOException 比如读写文件出错时
     */
    public static final String upload(String baseDir, MultipartFile file, String[] allowedExtension)
            throws IOException
    {
        /**
         * 判断文件名称长度
         */
        int fileNamelength = file.getOriginalFilename().length();
        if (fileNamelength > FileUploadUtils.DEFAULT_FILE_NAME_LENGTH)
        {
            throw new CustomException("文件名太长"+FileUploadUtils.DEFAULT_FILE_NAME_LENGTH);
        }
        /**
         * 判断文件大小
         */
        assertAllowed(file, allowedExtension);
        /**
         * 保存文件的路径和名称
         */
        String fileName = extractFilename(file);
        /**
         * 将配置文件设置的文件路径和新生成的文件路径进行拼接
         */
        File desc = getAbsoluteFile(baseDir, fileName);
        file.transferTo(desc);
        String pathFileName =  Constants.RESOURCE_PREFIX + "/" + fileName;
        return pathFileName;
    }

    /**
     * 编码文件名
     */
    public static final String extractFilename(MultipartFile file)
    {
        String fileName = file.getOriginalFilename();
        String extension = getExtension(file);
        fileName = DateUtil.format(new DateTime(), "yyyy/MM/dd") + "/" + encodingFilename(fileName) + "." + extension;
        return fileName;
    }

    private static final File getAbsoluteFile(String uploadDir, String fileName) throws IOException
    {
        File desc = new File(uploadDir + File.separator + fileName);

        if (!desc.getParentFile().exists())
        {
            desc.getParentFile().mkdirs();
        }
        if (!desc.exists())
        {
            desc.createNewFile();
        }
        return desc;
    }

    /**
     * 编码文件名
     */
    private static final String encodingFilename(String fileName)
    {
        fileName = fileName.replace("_", " ");
        fileName = DigestUtils.md5DigestAsHex((fileName + System.nanoTime()).getBytes());
        return fileName;
    }

    /**
     * 文件大小校验
     *
     * @param file 上传的文件
     * @return
     */
    public static final void assertAllowed(MultipartFile file, String[] allowedExtension)
    {
        long size = file.getSize();
        String fileName = file.getOriginalFilename();
        if (DEFAULT_MAX_SIZE != -1 && size > DEFAULT_MAX_SIZE)
        {
            throw new CustomException(fileName+"文件大小超出最大值");
        }

        String extension = getExtension(file);
        if (allowedExtension != null && !isAllowedExtension(extension, allowedExtension))
        {
                throw new CustomException(fileName+"文件类型不符合");
        }

    }

    /**
     * 判断MIME类型是否是允许的MIME类型
     *
     * @param extension
     * @param allowedExtension
     * @return
     */
    public static final boolean isAllowedExtension(String extension, String[] allowedExtension)
    {
        for (String str : allowedExtension)
        {
            if (str.equalsIgnoreCase(extension))
            {
                return true;
            }
        }
        return false;
    }

    /**
     * 获取文件名的后缀
     *
     * @param file 表单文件
     * @return 后缀名
     */
    public static final String getExtension(MultipartFile file)
    {
        String extension = FilenameUtils.getExtension(file.getOriginalFilename());
        return extension;
    }
}
